Procedure for measureing blood pressure

1. Have your subject be seated and relaxed with both feet on the floor and legs uncrossed. The back should be supported and the arm from which the reading is to be done should be at the same level as the heart and supported e.g. resting on desktop.
2. Fit the proper size of cuff to the subject's arm with bottom edge of the cuff 2-3 cm above the crease of the elbow ensuring that arrow marked on the cuff is in line with the artery.
3. Inflate the cuff while feeling the radial pulse. The pressure at which the pulse disappears gives a rough estimate as to the systolic pressure. Note this, and then deflate the cuff rapidly.
4. Feel for the brachial pulse, in order to guide the placement of the stethoscope. Note its location.
5. Now take the reading by inflating the cuff to 20-30 mm/Hg above the estimated systolic pressure, then deflate the cuff at the rate of 3mm/Hg per second or heart beat, while holding the stethoscope gently but firmly over the brachial artery. The systolic pressure is taken at the first appearance of clear, repetitive tapping sounds (Korotkoff sound 1.) and the diastolic pressure is taken at the disappearance of those sounds.
6. Record both pressures to the nearest 2mm/Hg.

Below is a good video clip for hearing what to expect, this person has high blood pressure at about 130 - 165.